Temperature-dependent reduction pathways of complexes fac-[Re(CO)3(N-R-imidazole)(1,10-phenanthroline)]+ (R = H, CH3)

Zeng, Q., Messaoudani, M., Vlcek Jr., A. and Hartl, F. ORCID: https://orcid.org/0000-0002-7013-5360 (2013) Temperature-dependent reduction pathways of complexes fac-[Re(CO)3(N-R-imidazole)(1,10-phenanthroline)]+ (R = H, CH3). Electrochimica Acta, 110. pp. 702-708. ISSN 0013-4686 doi: 10.1016/j.electacta.2013.02.018

Abstract/Summary

Peculiar reduction pathways of the complexes fac-[Re(imH)(CO)3(phen)]+ and fac-[Re(imCH3)(CO)3(phen)]+ (imH = imidazole, imCH3 = N-methylimidazole and phen = 1,10-phenanthroline) have been unravelled by performing combined cyclic voltammetric and in situ IR spectroelectrochemical experiments. In the temperature range of 293–233 K, the initial reduction of the phen ligand in [Re(imH)(CO)3(phen)]+ results in irreversible conversion of the imidazole ligand to 3-imidazolate by a rapid phen•−→ imH intramolecular electron transfer coupled with N H bond cleavage. This process is followed by second phen-localized 1e− reduction producing [ReI(3-im−)(CO)3(phen•−)]−, similar to the analogous 2,2'-bipyridine complex. In contrast to the bpy analogue, the stability of the phen•−-containing complexes is significantly affected by lowering the temperature. At 233 K, a secondary reaction occurs in both [Re(3-im−)(CO)3(phen•−)]− and [Re(imCH3)(CO)3(phen•−)]. The resulting products exhibit v(CO) wavenumbers indistinguishable from those of the parent phen•− complexes; however, their oxidation occurs at a considerably more positive electrode potential. It is proposed that these species are produced by a new C C bond formation between the C(2) site of 3-im− or imCH3 and the C(2) site of the phen•−ligand.

Additional Information	Paper from the 63rd Annual Meeting of the International Society of Electrochemistry 19 - 24 August 2012, Prague, Czech Republic (ELECTROCHEMISTRY FOR ADVANCED MATERIALS, TECHNOLOGIES AND INSTRUMENTATION)
Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/35323
Item Type	Article
Refereed	Yes
Divisions	Interdisciplinary centres and themes > Chemical Analysis Facility (CAF) Life Sciences > School of Chemistry, Food and Pharmacy > Department of Chemistry
Uncontrolled Keywords	Rhenium carbonyl; Imidazole; Phenanthroline; Reductive bond cleavage; Reduction pathway; IR spectroelectrochemistry
Additional Information	Paper from the 63rd Annual Meeting of the International Society of Electrochemistry 19 - 24 August 2012, Prague, Czech Republic (ELECTROCHEMISTRY FOR ADVANCED MATERIALS, TECHNOLOGIES AND INSTRUMENTATION)
Publisher	Elsevier
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